1. Field of the Invention
The present invention relates to an apparatus for protecting appliance controls for glass ceramic cooktops by providing double wall insulation and a low voltage fan.
2. Background Art
Dividing walls in cooktop appliances for control protection are generally known in the art. For example, U.S. Pat. No. 3,870,862 discloses a cooktop structural wall dividing the space below the cooktop into a cooking space portion and control space portion. The control space portion houses the electronic control components of the cooktop. The divider wall extends between a front sidewall and a rear sidewall below the cooktop and includes a pair of mounting bosses aligned with similar bosses on a left sidewall. The divider wall, the left sidewall and portions of the front sidewall and the rear sidewall surrounds the control space portion of the glass-ceramic cooktop. Unfortunately, the divider wall provides minimal insulating capabilities and is costly to assemble with the rest of the cooktop assembly.
Air flow systems have been generally utilized for control protection purposes. For example, U.S. Pat. No. 3,859,499 discloses an air flow system for heat-cleaning ranges in which room air is drawn through air inlets located along the sides and top of an oven opening. The air passes through a space between the range outer casting and the inner oven cabinet. A blower draws air into the upper air flow passageway during an oven heat-cleaning cycle. The blower exhausts air to the atmosphere through a vented splash panel.
U.S. Pat. No. 4,983,799 discloses a ventilation circuit for cooling the electronic power system of a domestic appliance. The circuit includes a fan mounted in the vicinity of the rear wall of the appliance housing. The ventilation circuit is shaped in order to force air in a direction substantially parallel to the electronic power system. The bottom of the housing has a port which is arranged vertically in line with the ventilation space. Air is forced through the port and into the housing and is subsequently removed by suction.
In U.S. Pat. No. 4,191,875, a fan for circulating air through a induction cooktop housing and maintaining the temperature of the electronic components is disclosed. The fan includes a conventional electronic motor used to circulate air both in and out of the housing through various openings provided in the housing. The speed of the electric fan is proportional to the degree of induction heating of the heating elements. The conventional electronic motor used in the fan requires substantial voltage and is bulky. U.S. Pat. No. 4,549,052 discloses a cooling system for an induction cooking cartridge. The system includes an internal fan for cooling the various induction heating components. The cooking cartridge is constructed so that a unique air flow enters a mounting recess in at least two areas and enters a cartridge cavity at the bottom and the top. The air flow is directed over the induction heating circuitry for cooling and is exhausted through the fan to an exhaust conduit.
U.S. Pat. No. 4,951,646 discloses a blower for a ventilated glass-top cooking unit. Control equipment is mounted in a lower compartment of the cooktop housing along with a blower having an intake in the lower compartment and an outlet in a vent passageway. The blower draws a primary stream of air in from the front of the housing and through the lower compartment and expels it upward into the vent passageway. This current aspirates secondary streams of air from the upper and intermediate compartments by venturi action. As a result, the electronic control equipment in the lower compartment is actively cooled by incoming outside air. Unfortunately, the blower is always on during cooking and is therefore susceptible to burnout.
The present invention overcomes the above-mentioned disadvantages by providing an appliance control protection apparatus for glass ceramic cooktop which includes a double wall housing that is inexpensive to assemble and provides superior insulating capabilities. According to the invention, the electronic control unit, including the circuit boards, are confined within a double wall housing. The first inner wall is adhered to the underside of the ceramic glass panel of the cooktop. The outer wall snaps into position over the first wall and provides a spacing therebetween which may also be filled with insulating material to prevent transfer of the heat from the heating elements in the cooktop toward the electronics.
Another advantage of the present invention is an appliance control protection apparatus for a glass ceramic cooktop which includes a low voltage fan and a heat sensor. The electronic control unit in a glass ceramic cooktop contains components, such as relays and transformers, that create hot spots within the control housing. The fan is mounted within the control housing to dissipate heat without ducting. Preferably, the fan responds to the formation of hot spots, as detected by a heat sensor, by convecting the heat away from the hot spots toward other components within the control housing, only operating when a predetermined temperature level of a hot spot is recorded. The fan operates conveniently to distribute heat evenly due to its compact size. Moreover, the fan does not require the power consumption of previously known fans.